<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style type="text/css">
        html, body {
            margin: 0;
            height: 100%;
        }

        canvas {
            display: block;
        }
    </style>
</head>

<body onload="draw();">
</body>
<script src="https://cdn.bootcss.com/three.js/91/three.min.js"></script>
<script src="js/controls/OrbitControls.js"></script>
<script src="js/libs/stats.min.js"></script>
<script src="https://cdn.bootcss.com/dat-gui/0.7.1/dat.gui.min.js"></script>
<script src="js/Detector.js"></script>

<script>
    var renderer, camera, scene, gui, light, stats, controls, mesh, skeletonHelper, bones;
    var state = {

        animateBones : false

    };

    function initRender() {
        renderer = new THREE.WebGLRenderer({antialias: true});
        renderer.setPixelRatio(window.devicePixelRatio);
        renderer.setSize(window.innerWidth, window.innerHeight);
        renderer.setClearColor(0xeeeeee);
        //告诉渲染器需要阴影效果
        document.body.appendChild(renderer.domElement);
    }

    function initCamera() {
        camera = new THREE.PerspectiveCamera(45, window.innerWidth / window.innerHeight, 0.1, 1000);
        camera.position.set(0, 40, 50);
    }

    function initScene() {
        scene = new THREE.Scene();
    }

    //初始化dat.GUI简化试验流程
    function initGui() {
        gui = new dat.GUI();
        var folder = gui.addFolder( "General Options" );

        folder.add( state, "animateBones" );
        folder.__controllers[ 0 ].name( "Animate Bones" );

        folder.add( mesh, "pose" );
        folder.__controllers[ 1 ].name( ".pose()" );

        var bones = mesh.skeleton.bones;

        for ( var i = 0; i < bones.length; i ++ ) {

            var bone = bones[ i ];

            folder = gui.addFolder( "Bone " + i );

            folder.add( bone.position, 'x', - 10 + bone.position.x, 10 + bone.position.x );
            folder.add( bone.position, 'y', - 10 + bone.position.y, 10 + bone.position.y );
            folder.add( bone.position, 'z', - 10 + bone.position.z, 10 + bone.position.z );

            folder.add( bone.rotation, 'x', - Math.PI * 0.5, Math.PI * 0.5 );
            folder.add( bone.rotation, 'y', - Math.PI * 0.5, Math.PI * 0.5 );
            folder.add( bone.rotation, 'z', - Math.PI * 0.5, Math.PI * 0.5 );

            folder.add( bone.scale, 'x', 0, 2 );
            folder.add( bone.scale, 'y', 0, 2 );
            folder.add( bone.scale, 'z', 0, 2 );

            folder.__controllers[ 0 ].name( "position.x" );
            folder.__controllers[ 1 ].name( "position.y" );
            folder.__controllers[ 2 ].name( "position.z" );

            folder.__controllers[ 3 ].name( "rotation.x" );
            folder.__controllers[ 4 ].name( "rotation.y" );
            folder.__controllers[ 5 ].name( "rotation.z" );

            folder.__controllers[ 6 ].name( "scale.x" );
            folder.__controllers[ 7 ].name( "scale.y" );
            folder.__controllers[ 8 ].name( "scale.z" );

        }
    }

    function initLight() {
        scene.add(new THREE.AmbientLight(0x444444));

        light = new THREE.PointLight(0xffffff);
        light.position.set(0, 50, 0);

        //告诉平行光需要开启阴影投射
        light.castShadow = true;

        scene.add(light);
    }

    function initModel() {

        //辅助工具
        var helper = new THREE.AxesHelper(50);
        scene.add(helper);

        //制作模型
        var segmentHeight = 6; //每一节骨骼的的高度
        var segmentCount = 4; //总节数
        var height = segmentHeight * segmentCount; //总高度
        var halfHeight = height * 0.5; //总高度一半的高度

        var sizing = {
            segmentHeight : segmentHeight,
            segmentCount : segmentCount,
            height : height,
            halfHeight : halfHeight
        };

        var geometry = createGeometry( sizing ); //创建几何体
        var bones = createBones( sizing ); //创建骨骼
        mesh = createMesh( geometry, bones ); //创建网格模型

        //mesh.scale.multiplyScalar( 1 );
        scene.add( mesh );

    }

    //创建集合体
    function createGeometry ( sizing ) {

        var geometry = new THREE.CylinderGeometry(
            5,                       // 顶部圆柱体的半径
            5,                       // 底部圆柱体的半径
            sizing.height,           // 圆柱体的高度
            8,                       // 圆柱周围的分段面数
            sizing.segmentCount * 3, // 沿圆柱体高度的面的行数
            true                     // 圆柱体的末端是打开
        );

        //添加绘制第二个纹理的面
        var len = geometry.faces.length;

        for(var i=0; i < len; i++){
            var face = geometry.faces[i].clone();
            face.materialIndex = 1;
            geometry.faces.push(face);
        }

        //将vertexUv报错解决掉
        var len = geometry.faceVertexUvs[0].length;

        for(var i=0; i < len; i++){
            geometry.faceVertexUvs[0].push(geometry.faceVertexUvs[0][i]);
        }

        //遍历几何体所有的顶点
        for ( var i = 0; i < geometry.vertices.length; i ++ ) {

            //根据顶点的位置计算出骨骼影响下标和权重

            var vertex = geometry.vertices[ i ];
            var y = ( vertex.y + sizing.halfHeight );

            var skinIndex = Math.floor( y / sizing.segmentHeight );
            var skinWeight = ( y % sizing.segmentHeight ) / sizing.segmentHeight;

            geometry.skinIndices.push( new THREE.Vector4( skinIndex, skinIndex + 1, 0, 0 ) );
            geometry.skinWeights.push( new THREE.Vector4( 1 - skinWeight, skinWeight, 0, 0 ) );

        }

        return geometry;

    }

    //创建骨骼
    function createBones ( sizing ) {

        bones = [];

        var prevBone = new THREE.Bone();
        bones.push( prevBone );
        prevBone.position.y = - sizing.halfHeight;

        for ( var i = 0; i < sizing.segmentCount; i ++ ) {

            var bone = new THREE.Bone();
            bone.position.y = sizing.segmentHeight;
            bones.push( bone ); //添加到骨骼数组
            prevBone.add( bone ); //上一个骨骼定义为父级
            prevBone = bone;

        }

        return bones;

    }

    function createMesh ( geometry, bones ) {

        var material = new THREE.MeshPhongMaterial( {
            skinning : true,
            color: 0x156289,
            emissive: 0x072534,
            side: THREE.DoubleSide,
            flatShading: true
        } );

        var lineMaterial = new THREE.MeshBasicMaterial({
            skinning : true,
            wireframe: true
        });

        mesh = new THREE.SkinnedMesh( geometry,	[material, lineMaterial] );
        var skeleton = new THREE.Skeleton( bones ); //创建骨架

        mesh.add( bones[ 0 ] ); //将骨骼添加到模型里面

        mesh.bind( skeleton ); //模型绑定骨架

        //添加骨骼辅助标记
        skeletonHelper = new THREE.SkeletonHelper( mesh );
        skeletonHelper.material.linewidth = 2;
        scene.add( skeletonHelper );

        return mesh;

    }

    //初始化性能插件
    function initStats() {
        stats = new Stats();
        document.body.appendChild(stats.dom);
    }

    function initControls() {

        controls = new THREE.OrbitControls(camera, renderer.domElement);

        // 如果使用animate方法时，将此函数删除
        //controls.addEventListener( 'change', render );
        // 使动画循环使用时阻尼或自转 意思是否有惯性
        controls.enableDamping = true;
        //动态阻尼系数 就是鼠标拖拽旋转灵敏度
        //controls.dampingFactor = 0.25;
        //是否可以缩放
        controls.enableZoom = true;
        //是否自动旋转
        controls.autoRotate = false;
        controls.autoRotateSpeed = 0.5;
        //设置相机距离原点的最远距离
        controls.minDistance = 1;
        //设置相机距离原点的最远距离
        controls.maxDistance = 2000;
        //是否开启右键拖拽
        controls.enablePan = true;
    }

    function render() {
        var time = Date.now() * 0.001;

        //Wiggle the bones
        if ( state.animateBones ) {

            for ( var i = 0; i < mesh.skeleton.bones.length; i ++ ) {

                mesh.skeleton.bones[ i ].rotation.z = Math.sin( time ) * 2 / mesh.skeleton.bones.length;

            }

        }


        controls.update();
    }

    //窗口变动触发的函数
    function onWindowResize() {

        camera.aspect = window.innerWidth / window.innerHeight;
        camera.updateProjectionMatrix();
        renderer.setSize(window.innerWidth, window.innerHeight);

    }

    function animate() {
        //更新控制器
        render();

        //更新性能插件
        stats.update();

        renderer.render(scene, camera);

        requestAnimationFrame(animate);
    }

    function draw() {
        //兼容性判断
        if (!Detector.webgl) Detector.addGetWebGLMessage();

        initStats();
        initRender();
        initScene();
        initCamera();
        initLight();
        initModel();
        initControls();
        initGui();

        animate();
        window.onresize = onWindowResize;
    }


</script>
</html>